Method of sealing containers with laminated closures

ABSTRACT

1,011,800. Packages. PETROLITE CORPORATION. Aug. 22, 1962 [Aug. 23, 1961; April 16, 1962], No. 32271/62. Addition to 1,011,796. Drawings to Specification. Heading B8C. [Also in Division B5] A container comprises a container body and an unarticulated closure member at least one of these being of the laminated sheet material of the parent Specification, the closure member being sealed to the body by the exudation of the thermoplastic adhesive from one or more avenues of exit in edge regions of the sheet material. The container may be a circular tub (Figs. 5-10, not shown, or a single or double compartment tray (Figs. 2-9, not shown), the closure member being a flat sheet of the laminate which may be provided with a transparent window by removal of a portion of the outer plies, or by providing a tearaway portion in the outer ply, the window either being formed by the adhesive layer or by a further inner film layer of glassine, regenerated cellulose, cellulose acetate vinyl, or polystyrene. A multi-container strip may be filled with contents and covered with a strip of the laminated sheet which is then cut into individual closure members with a heated blade which simultaneously effects the sealing of the closure members to the containers.

Dec. 13, 1966 G. 5. RUMBERGER 3,290,856

METHOD OF SEALING CONTAINERS WITH LAMINATED CLOSURES Original FiledApril 16, 1962 5 Sheets-Sheet 1 7 6/! FIGURE I I I I I I FIGURE 6 20 a22 r J I r i 2/ I 5 m m a I 1g FIGURE2 Z3 I v FIGURE 7 FIGURE 3 FIGURE 9IN VEN TOR. O/PGE 6 Fl/MEf/Q'GER FIGURE 5 5 s. G. RUMBERGER 3,290,855

METHOD OF SEALING CONTAINERS WITH LAMINATED CLOSURES Original FiledApril 16, 1962 5 Sheets-Sheet 2 FIGURE l5 INVENTOR 6EOR6E 4. RZ/MEERGE/PDec. 13, 1966 G. e. RUMBERGER 3,290,856

METHOD OF SEALING CONTAINERS WITH LAMINATED CLQSURES Original'FiledApril 16, 1962 5 Sheets-Sheet 3 mvzmon. 60R6E a Rz/MA'ERGER BY FIGU RE2| Arm/Mfr United States Patent 3,290,856 METHOD OF SEALING CONTAINERSWITH LAMINATED CLOSURES George G. Rumherger, Kalamazoo, Micln, assignorto KVP Sutherland Paper Company, Kalamazoo, Mich, a corporation ofDelaware Original application Apr. 16, 1962, Ser. No. 187,592, nowPatent No. 3,194,479, dated July 13, 1965. Divided and this applicationMar. 11, 1965, Ser. No. 438,931

4 Claims. (CI. 5339) The present invention relates to containers and ismore particularly concerned with container of the type in which aclosure member is sealed to a container body by extrusion of athermoplastic laminant adhesive from the container body or closuremember. The instant application is a division of Serial No. 187,592,filed April 16, 1962, now US. Patent No. 3,194,479 which in turn is acontinuation-in-part of my copending application Serial No. 133,439,filed August 23, 1961, now US. Patent No. 3,194,474. My priorapplication inter alia discloses a laminated sheet material havingsufiicient thermoplastic laminant adhesive interposed between the twoouter sheets or plies so that it is particularly useful in making cartonblanks and cartons which may be sealed by extrusion of the adhesive fromcuts or slits provided in closure members. The present inventionutilizes such type of laminated sheet material and relates in particularto containers having a closure member which is sealed to the containerbody by extrusion of adhesive from the container body or closure memberin the closure member edge, e.g., peripheral or circumferential, areas.

Many types of containers provided with detachable and articulatedclosure members are currently available. In general, they may be dividedinto two categoriescontainers which may be sealed without the employmentof additional adhesive and containers which cannot be sealed unless thesealing areas are coated with adhesive. Containers which may be sealedwithout employment of additional adhesive are sometimes referred to asself-sealing containers. Such containers are provided with an adhesivesurface during the fabricating operation, as by the surface applicationof hot melts, lacquers, latices, organosols, and the like, and aregenerally preferred to other containers since filling and sealingthereof may be performed in a simple and facile manner. In someinstances, to prevent the adhesive surfaces of one empty container,comprising a closure member and a container body, from adhering toanother empty container while they are being stacked and shipped,protective material may overlie the adhesive surface, but must bereadily removable therefrom prior to scaling of the closure member tothe container body. Such protective material presents many problems andalso increases the cost of the container.

In the packaging of many materials it is desirable to have a covermember which is highly protective and which can be readily sealed to acontainer body member. Although the desirability of having a laminatedsheet for a cover, especially one laminated with a moisture or gas proofthermoplastic, has long been recognized, it has not been possible toprovide such a closure member using the common topical applications ascited above due to delamination of the sheet material or other factorscontributing to the loss of its protective properties.

Thus, the need for a container having a container body and closuremember which may be sealed to each other in a simple and facile mannerhas long been recognized. This need has become more acute during thepast decade since many advantages are attainable by packaging foodstuffsand the like in containers, such as these formed 3,290,856 Patented Dec.13, 1966 from paper, plastic, metal, glass, ceramics, and the like. As aconsequence, the .pakagingindustry has been confronted with the problemof supplying containers which may be sealed in a simple and facilemanner and which will remain sealed until opened by the consumer. Thisproblem has not been adequately solved up to the present.

Accordingly, it is an object of the present invention to provide acontainer'ha'ving an improved seal between the closure member and thecontainer body, in which at least one of said closure member andcontainer body is of laminated sheet material.

An additional object is to provide an edge-sealing container in whicheither the container body or closure member or both are of laminatedsheet material.

Another object of the invention i to provide a laminated closure memberwith a circumferential slit in at least one ply thereof from which athermoplastic laminant adhesive is extruded for sealing the closuremember to the bearing edge of a container body, and the com-bination ofsuch closure member with such container body.

A further object of the invention is to provide a container having acontainer body constructed of laminated sheet material in combinationwith a container closure member, said closure member being sealed tosaid container body at a bearing edge of said container body bythermoplastic laminant adhesive extruded through a circumferential slitor cut in the inner ply of said container body.

A still further object is the provision of a container having acontainer body and a closure member, in which said closure member nestsupon a bearing edge of said container body and is secured thereto bymeans of thermoplastic laminant adhesive extruded outwardly from the cutedge of said container closure member peripherally or circumferentially.

Still another object is the provision of a container having a containerbody and a container closure member, whether or not articulated thereto,and wherein the closure member is provided with one or more slits in itsinner ply in the edge areas thereof, said closure member being oflaminated sheet material and having such slits in said edge areaextending circumferentially along unarticulated sides thereof.

Still an additional object of the invention is the provision of acontainer having a container body and a container closure member, saidcontainer body having a bearing edge for support of said closure member,and said closure member being constructed of laminated sheet materialand being provided with an avenue or path of exit of the thermoplasticadhesive laminant to the bearing edge of said container body or anextension thereof, for sealing said closure member to said body memberin the edge areas thereof upon the application of thermoplastic laminantadhesive activating conditions.

Another object is the provision of a container having a container bodyand a closure member in sealing engagement therewith, one of saidmembers being of lami- 'nated sheet material containing a sutficientamount of thermoplastic adhesive laminant between its plies to eX- trudethrough avenues of exit and into areas of contact with the othercontainer member, i.e., into areas of sealing engagement, uponapplication of thermoplastic adhesive laminant activating conditions.

It is another object of the present invention to provide a laminatedclosure member with a slit or slits in the edge areas of a ply or pliesthereof for extrusion of thermoplastic laminant adhesive through one orboth sides of the closure member and into contact with a container bodywhen in sealing engagement therewith, and the combination of suchcontainer 'body and closure member.

It is still another object to provide a laminated closure member withone or more slits in unarticulated edge areas thereof through which slitor slits thermoplastic laminant adhesive is extruded for sealing theclosure member to a bearing edge of the container body, and thecombination of such container body and closure member.

It is a still further object of the present invention to provide alaminated closure member with a diagonal slit at each of itsunarticulated corners in registry with the junctures of underlyingfiaps, and containers embodying the same.

Yet another object of the present invention resides in a containerhaving a closure member sealed thereto by extrusion of thermoplasticlaminant adhesive in the closure member edge areas, whethercircumferentially, peripherally, or through one or more slits or cuts inthe said edge areas.

Still a further object of the present invention is to provide acontainer with a self-gasketed locked-in closure member.

Other objects and advantages of the present invention will be apparentto one skilled in the art and still other objects of the invention willbecome apparent hereinafter.

The present invention, therefore, is concerned with containers in whicheither the container body or the closure member, or both, are oflaminated sheet material, and which are or may be sealed in the edgeareas of said closure member by the extrusion of thermoplastic laminantadhesive from either the closure member, when of laminated sheetmaterial, or the container body, when it is constructed of laminatedsheet material. Whichever of the members, that is, the closure member orthe body member, is constructed of laminated sheet material, comprisesat least two plies of sheet material bonded together by a thermoplasticlaminant adhesive. One or both of the outer plies of the laminated sheetmaterial are provided with one or more slits in the edge areas thereofthrough which thermoplastic laminant adhesive may be extruded uponapplication of heat, heat and pressure, or even pressure alone in somecases. Alternatively, the raw cut edges of either the closure member, orcontainer body, whichever is constructed of laminated sheet material,may serve alone or together with slits or cuts in the edge areas as anavenue or path of exit of the thermoplastic adhesive laminant. Theclosure member, whether or not articulated along one side thereof, uponcontainer closure, usual- 1y rests against bearing edge provided as apart of the container body. An extension of such bearing edge may extendupwardly in juxtaposition to the cut edge of a container closure member.Upon the application of thermoplastic laminant adhesive activatingconditions with closure member in place, either at the edge areas of theclosure member itself if of the laminated sheet material, or at theoutside of said container body opposite the edge area of the closuremember especially when the container body is constructed of laminatedsheet material, but even when the closure member is constructed oflaminated sheet material, the thermoplastic laminant adhesive iseffectively extruded either outwardly of the cut edges of the closuremember and into .contact with a wall, bearing edge, or extension of abearing edge of the container body, or downwardly through openings,e.g., slits or cuts located in the ply of the closure member injuxtaposition to a bearing edge of the container body, or through bothplies of :the container closure member and into contact with a bearingedge of the container body as well as into contact with a turned over orcrimped edge of the container body, or through a combination of the cutedge and peripheral, circumferential, or other slits in one or more ofthe plies of the closure member which are located in the edge areas ofsaid closure member. Upon congealment or setting of the thermoplasticadhesive, an effective seal is provided between the closure member andthe container body. When it is the container body rather than theclosure member that is constructed of laminated sheet material, one ormore slits or cuts may be provided in the edge areas adjacent a bearingedge of said container, if any, from which thermoplastic laminantadhesive may be extruded into contact with the closure member at theedge areas thereof for sealing of said closure member to said containerbody upon the application of thermoplastic adhesive laminant activatingconditions, as to the exterior of said container body opposite the edgeareas of said closure member. Depending upon the material ofconstruction of the container body and closure member, the container mayor may not be hermetically sealed, but in any event it is possible ifdesired to effect a hermetic seal of the container. In the foregoingmanner, according to the invention, it is now for the first timepossible to provide effectively sealed, and if desired hermeticallysealed, containers of the type already indicated, in which the containerclosure member is sealed at its edge areas to the container body, i.e.,in the areas of sealing engagement, by means of self-contained laminantadhesive to provide sanitary, tamper-proof, protective, and compositecontainers, which may nevertheless be readily opened at will.

For a better understanding of the present invention, reference may behad to the accompanying drawings wherein the parts are numbered, thesame numbers are used to refer to the corresponding parts throughout,and where- FIGURE 1 is an enlarged fragmentary vertical section of alaminated sheet material employed in the present invention;

FIGURE 2 is a front elevational view of a container embodying thepresent invention;

FIGURE 3 is a top plan view thereof;

FIGURE 4 is an enlarged fragmentary vertical section taken along lineIV-IV of FIGURE 3 to show in detail the seal between the laminatedclosure member and the container body;

FIGURE 5 is an enlarged fragmentary vertical section similar to FIGURE 4showing another embodiment of the invention; M

FIGURE 6 is a front elevational view of a multi-chambered containerhaving tear-out sections;

FIGURE 7 is a top plan view of the container shown in FIGURE 6;

FIGURE 8 is an enlarged fragmentary vertical section taken along lineVIIIVIII of FIGURE 7;

FIGURE 9 is an enlarged fragmentary vertical section similar to FIGURE 8showing another embodiment of the present invention;

FIGURE 10 is a front perspective view of a substantially cylindricalcontainer;

FIGURE 11 is a top plan View of the container shown in FIGURE 10assuming that the closure member is in sealing engagement with thecontainer body;

FIGURE 12 is an enlarged fragmentary vertical section taken along lineXIIXII of FIGURE 11;

FIGURE 13 is an enlarged fragmentary vertical section similar to FIGURE12 showing another form of the invention;

FIGURE 14 is an enlarged fragmentary vertical section similar to FIGURE13 showing still another form of the invention;

FIGURE 15 is a top plan view of a container provided with a locked-inclosure member;

FIGURE 16 is an enlarged fragmentary vertical section taken along lineXVI-XVI of FIGURE 15;

FIGURE 17 is an isometric view of a container provided with anarticulated closure member;

FIGURES 18 and 19 show different embodiments of a corcrltainer providedwith an articulated closure member; an

FIGURES 20 and 21 show still another embodiment of a container providedwith an articulated closure member showing the flaps in various stagespreparatory to scaling the closure member to the bearing edge of thecontainer body.

Referring now to the drawings, FIGURE 1 is an enlarged cross sectionalview of a portion of a laminated sheet material 23 utilizable accordingto the invention, as it might be formed by laminating a fifty pound perream (24 x 36-500) .0035 inch thick dry waxed paper sheet 23b to a .012inch thick paperboard sheet 23a with .0065 inch of thermoplasticlaminating adhesive 23c.

Referring now to FIGURE 2 of the drawings, there is illustrated acontainer, generally indicated at 20, which comprises a container body21, including an outwardly extending peripheral rim or flange 22,forming a bearing edge to support closure member 23, shown in sealingengagement therewith. As best viewed in FIGURES 1 and 4, closure member23 comprises two plies of sheet materials 23a and 23b laminated togetherwith thermoplastic laminant adhesive 230.

Although the closure member 23 is fabricated of laminated material whilethe container body 21 is fabricated of unlaminated material, thematerials can be reversed. I prefer to employ a laminated closure memberin the majority of embodiments shown herein since such constructiongenerally results in a more economically sealed container provided withthe same preferred type of characteristics, and allows for choice of abody structure from a wide variety of structural and protectivematerials.

The laminated sheet material employed in the container or in the closuremember, or in both according to some embodiments, contains sufiicientthermosplastic laminant adhesive so that, upon application ofthermoplastic laminant adhesive activating conditions to the edge areasof the container closure, as where such upon closing of the containerabuts the bearing edge of the container, extrusion of the thermoplasticlaminant adhesive from the cut edges of the closure member or containerconstructed of such laminated sheet material, and through anyinterstices, such as cuts or the like, or a single cut, provided in theedge areas of the closure member or the container itself, results.

The laminated sheet material employed usually contains at least aboutfifty-five pounds and preferably greater amounts of thermoplasticlaminant adhesive 230 per standard 24 inches by 36 inches by 500 sheetream of the laminated sheet material 23. This permits unprecedentedsealing characteristics. In addition, the plies 23a and 23b of thelaminated sheet material 23 have a porosity of at least five andpreferably ten seconds. This permits the desired extrusion and allowsscoring or drawing and provision of the necessary openings, e.g., slitor slits, without fragmentation. This basic combination appears to befundamental for adequate heat-sealing of the containers to their closuremembers or vice versa.

I have found it necessary to use sheets having a porosity, as defined bythe air resistance test of TAPPI (Technical Association of the Pulp andPaper Industry) method T460 M49, of at least five seconds and preferablyten seconds or above. By contrast, I have found that porous tissues, orlike open sheets having a porosity value of less than one and seldomgreater than two second, cannot be used.

I have also found porous tissues lacking in the strength necessary towithstand scoring and subsequent folding or drawing, and my thinnestpaper sheets are therefore generally chosen with a Mullen dry burststrength of ten or above, and preferably fifteen or above, as determinedby TAPPI procedure T403. However, strength may not be critical, and isgenerally not as critical as porosity, especially when stretchablematerials such as creped papers, or plastic films such as polyethyleneor polyvinyl chloride films, are used as the thinnest ply of laminatedsheet material.

The requisite openings, interstices, or apertures in one or both of theplies of the closure member or container body may be and preferably areone or more slits or cuts in the edge areas and/or openings in the rawcut 6 edges thereof, and their disposition may be either wholly orpartly longitudinal, transverse, diagonal, circumferential, or the like.

For the purpose of sealing closure member 23 to the bearing edge formedby theperipheral flange 22 of the container body 21, a circumferentialslit or slits 24 (see FIGURE 4) are provided in the edge areas of ply23b). Containers which are not subjected to much abuse may be providedwith a closure member having a single circumferential slit. After thecontainer body 21 is filled, closure member 23 is placed in sealingengagement therewith. (Sealing engagement is also shown in FIGURES 2, 4,5, 8, 9, 12, 13, 14 and 16, for example.) The amount of thermoplasticadhesive bonding the several plies or laminations is sufficient so thatupon application of adhesive activating conditions, e.g., by applyingsuitable heat or heat and pressure, as with an appropriate sealing ironor by microwave heating or the like, to the edge areas of the closuremember, a small amount of thermoplastic laminant adhesive 230 isextruded through the slits 24 against the bearing edge of peripheralflange 22 of container body 21, sealing the closure member 23 theretoupon setting of the adhesive. Extrusion of the adhesive 230 may also beeffected solely by heat to raise the temperature thereof beyondincipient tackiness, but a more rapid and effective seal is generallyobtained if both heat and pressure are employed.

As the adhesive 23c is extruded through the slits 24, some of theadhesive is also extruded out of the openings in the cut ends of theclosure member 23 for effectively sealing the raw cut edges of the outerplies. Thus, with this type of seal, the closure member 23 can behermetically sealed to an impervious container body, and wicking ofvapors or liquids thrpugh the cut edges precluded. With porous containerbodies, an effective seal is thereby provided.

To improve salability of the contents of the container, that is, toenable the buyer to select the contents as to appearance, quality,color, or the like, a closure member for a container body may beprovided with a transparent window. By providing an aperture in thecentral portion of the plies 23a and 23b of the closure member 23,certain thermoplastic laminant adhesives 230, which are non-tacky atambient temperatures and substantially transparent, may serve as awindow. With such an arrangement, an economical window-type closuremember is made available since the adhesive 230 is also employed forsealing the closure member to the container body 21.

When it is desired to secure a window exhibiting different propertiesthan those obtainable with the laminant adhesive 230, a separate sheetof material 35 (see FIG URE 5) such as glassine, cellophane, vinyl film,polystyrene, cellulose acetate, or the like, may be secured to a closuremember 33 as by extrusion of adhesive 33c through a circumferential slit34 encircling the aperture or window opening therein, or by othersuitable adhesive on their surfaces.

The laminated sheet material removed from the sheet in providing thewindow opening area may be conveniently used for other smaller lids forother containers. A tearout window cover may be provided by perforatingthe boundary of an area in cover 23 or 33 and allowed to remainsuperimposed over the window, as for protection during shipping,imprinting, storage, etc, which tearout is kept intact until removed atthe point of sale.

In FIGURES 6 through 8 inclusive is shown another form of the invention.Referring to FIGURE 6, a container, generally indicated at 60, comprisesa container body '61 provided with two chambers 61a and 6111 which maybe filled with the same or different contents. Container body 61, asshown in FIGURE 8, includes an outwardly extending top peripheral flange62 having an upended skirt 62a. Laminated closure member 63 is supportedby the bearing edge formed by peripheral flange 62 and is properlyaligned by the upended skirt 62a. The closure member 63 includes twoouter sheets 63a and 63b laminated together with a thermoplasticlaminant adhesive 630. The edge areas of ply 63b are provided with asingle circumferential slit 64 through which is extruded, uponapplication of adhesive activating conditions, sufiicient thermoplasticlaminant adhesive" 63c for sealing the closure member 63 to the bearingedge formed by flange 62. When desired, ply 63b of closure member 63 maybe provided with a centrally disposed transverse slit employed forextruding adhesive 630 for sealing off chamber 61a from chamber 611).Thermoplastic laminant adhesive 63a is also extruded through cut edgesof closure member 63 against the inner face of the skirt 62a forincreasing the sealing area of the adhesive as well as preventingwicking through the end thereof.

For removal of contents from one of the chambers af ter the container 60has been sealed, closure member 63 may be provided with tearout sections65 and 66 defined by lines of severance or weakening 67 and 68respectively. Depending upon the thickness and strength of thethermoplastic laminant adhesive 630, the lines of severance may eitherextend thereto or else a thin web may be allowed to remain in outer ply63a for joining tearout sections to the periphery of closure member 63.If ply 63b is sufficiently thin, it need not be perforated but may beleft intact, and will be torn upon removal of top ply 63a when thetearout is removed as a cohesive unit. Such a construction is shown inFIGURE 9.

In the sealing of some containers, it may be unnecessary to employ aclosure member having a circumferential or other edge area slit sinceextrusion of the thermoplastic laminant adhesive from the cut edges ofthe closure member eflfects a sufficient seal when in contact with askirt or other suitable portion of the container body. This form of theinvention is illustrated in FIGURE 9 of the drawings wherein the closuremember 93 is sealed to the container body 91 only by extrusion ofthermoplastic laminant adhesive 930 from the cut edges thereof againstthe inner face of the bearing edge extension 92a.

Another form of the invention is shown in FIGURES through 12. As bestshown in FIGURE 10, a container, generally indicated at 100, comprises asubstantially cylindrical container body 101 having a leakproof or otherbottom suitably secured thereto or integral therewith. The containerbody 101 may also be of the inverted truncated cone shape, or any otherconventional construction or form.

For the purpose of supporting a closure member 103 in the container body101, the upper portion thereof is provided with an annular ridge 102(see FIGURE 12). A concentric skirt 102a extends upwardly from the outerperiphery of ridge 102 and aligns closure member 103 With the rim 102aand the container body 101. Both skirt 102a and ridge 102 form bearingedges for support of closure member 103. Closure member 103 is oflaminated construction, having plies 103a and 10312 laminated togetherby a thermoplastic laminant adhesive 1030. The edge areas of the closuremember are upended to obtain a snug fit between concentric skirt 102aand the closure member 103. Such construction may provide a goodfrictional seal for closing the container after a portion of thecontents have been removed, or when a container is reused for storingleft-overs or the like, provided minimal adhesive is used to effect theinitial seal.

To provide an effective seal between closure member 103 and containerbody 101, a circumferential slit 104 is disposed in the outer ply 103]]through which is exeral construction as described for FIGURES 10 through12, including an annular ridge 132 for supporting and limiting insertionof a closure member 133 into a container generally indicated at 130. Themain difference is that the container body 131 is of laminated materialwhile the closure member 133 is of unlaminated material. Although ridge132 forms a bearing edge for closure member 133, the closure member alsoforms a bearing edge, as for applying sealing means from outside thecontainer. A seal is effected by extrusion of adhesive from acircumferential slot in the edge area of the container body uponapplication of adhesive activating conditions.

In FIGURE 14, a container generally indicated at is substantially thesam as the container 130 shown in FIGURE 13 including a ridge 142 forsupporting and limiting insertion of aclosure member 143 into containerbody 141. In this embodiment, the upper portion of the closure member143 is turned outwardly to provide an additional sealing area and toallow container body 141 to provide a second bearing edge. Outer ply14111 of container body 141 is provided with a circumferential slit inconcentric skirt 142a thereof for extrusion of thermoplastic laminantadhesive 141c against the inner face of the upended edge area of closuremember 143. Additional thermoplastic laminant, adhesive 141c is extrudedout of the cut edge of the container body Wall against the adjacentsurface of the outwardly turned portion of the closure member, therebyproviding a double seal between closure member 143 and container body141.

With each of the embodiments described heretofore, a closure member isplaced on or inserted into a container body and sealed to a bearing edgethereof without locking the closure member to the container body or viceversa. Such constructions enable foodstuffs, produce, or the like to besealed in containers in a simple and facile manner since the onlyapparatus necessary is, for example, an appropriate sealing mechanism.For other applications of the invention, however, it may be desirableand preferred to reinforce the sealing area as well as entrap extrudedthermoplastic laminant adhesive. To this end, a container generallyindicated at in FIG- URE 16, having the same general construction asdescribed in the embodiments shown in FIGURES 2 through 14, is providedwith a container body 151 having a turned over or crimped top portion157 for mechanically locking a closure member 153 to the container bodybefore, during, or after the sealing operation. Although such containerconstruction requires more complicated apparatus for turning over thetop portion 157 of the container body 151, the advantages sometimes morethan offset the additional cost involved. After application of adhesiveactivating conditions to the closure area, the contents in the containermay be warmed or frozen without rupturing the seal.

In the various embodiments described heretofore the closure members arenot an integral part of the container body. In the embodimentsillustrated in FIGURES 17 through 21, the closure members arearticulated to one of the wall panels. More specifically, and as shownin FIGURE 17, a container or erected carton, generally indicated at 170,comprises a carton body 171 having four standard wall panels and abottom. Articulated to the wall panel 171a is a closure member 173, andarticulated to the remaining wall panels are narrow flaps 172 foldedinwardly at lines of articulation so as to be normal to their respectivewall panels. As the following description proceeds it will becomeapparent that the narrow flaps 172 provide a sealing area and bearingedge for the closure member 173.

One or more slits 174 are provided circumferentially in the edge areasof the unarticulated sides of closure 9 Conditions, the thermoplasticlaminant adhesive extrudes through the slits 174 and seals the closuremember to the carton body.

Erected carton 180, as shown in FIGURE 18, is generally similar to thecarton 170 including wall panels, bottom, narrow flaps articulated tothe wall panels, and the articulated closure member 183. Instead ofdisposing the slits parallel to the top flap or closure edges, asillustrated in closure member 173 of FIGURE 17, the slits 184 arediagonally disposed in the circumferential edge areas of closure member183 for providing the sealing area between the closure member 183 andthe bearing edge provided by narrow flaps 182. Obviously the slits canbe arranged in various patterns.

Carton 190 shown in FIGURE 19 is also generally similar to carton 170 ofFIGURE 17. In this embodiment, carton 190 is provided with side flaps192a and 19212 and front flap 1920 articulated to the wall panels.Junctures or flush butt joints 198 are formed between the side flaps andthe front flap when they are folded inwardly and normal to the wallpanels. The side and front flaps provide a bearing edge for sealing ofthe closure member (cover flap 193) to the container body. Closuremember 193 is provided with additional diagonal slits 194a which overliethe junctures 198 when closure member 193 is in sealing engagementtherewith. Thus, when the thermoplastic laminant adhesive is extrudedfrom the slits in the closure member upon application of adhesiveactivating conditions, the adhesive seals the closure member 193 to thecarton body and the narrow flaps to each other at their junctures 198.

FIGURES 20 and 21 show another form of the invention. The cartonconstruction is generally similar to that shown in FIGURE 19 except thatthe side flaps are articulated to the front flap by webs 209. Such flapconstruction reinforces the top of the erected carton and forms a rigidbearing edge. FIGURE 20 shows the flaps 202 preparator to folding andFIGURE 21 shows the flaps 202 in the folded position and the webbedcorner junctures 208 therebetween, Upon application of adhesiveactivating conditions to the carton, after closure member 203 is insealing engagement with the bearing edge of the carton body, adhesive isextruded through slits 204 and 204a for sealing the closure member tothe carton body and the flaps to each other at their junctures 208. Asingle slit 204 may replace the two slits 204; alternatively an addedslit may also be present in the circumferential edge areas of flap 203or slits 204a may lie adjacent junctures 203.

The closure member and the carton body may be of the same construction,as when articulated thereto, or the closure member may be separate fromthe carton body. In such case, it is unnecessary that both the closuremember and the carton body he of laminated material. As to anunarticulated closure member, it is a matter of choice as to whether theclosure member and/ or the container body are made of laminated sheetmaterial. Moreover, it is to be understood that, although the laminatedsheet materials employed in fabricating the closure members and/ or thecontainer bodies basically comprise two plies laminated to each other bythermoplastic laminant adhesive, additional sheets or plies may beincluded or suitably laminated thereto.

I have found it preferable to provide the necessary openings, usually inthe form of slits or incisions, when desired for extrusion of thelaminating adhesive used in the construction of my heat sealingcontainers, that is, in the container body and/ or closure member, atsome stage after the laminating step and before, during or after theformation of scores and cutouts and before, during, or after anybackcutting or drawing, which is necessary or desired for thedelineation of the closure member and/ or container body, and preferablyafter the printing of any required indicia or artwork which must be inregistry thereon. In this way the means for extrusion of the laminatingadhesive are located in exactly the desired zones as required for theformation of the desired bond or seal, and laminant adhesive is notrandomly extruded as would be the case if openings were placed in one orboth of the plies in advance of the laminating step. Furthermore, due tothe character of the slits provided and the amount of adhesive used aslaminant, it is necessary that they be provided following the laminationstep, as this prevents unwanted transfer of the molten hot melt used inthe laminating step through the sheet prior to the moment of itsintended use in sealing of the container.

It is apparent from the foregoing that either the closure member or thecontainer body :is constructed of laminated sheet material and that theother member may be and usually is constructed of a different material.

One of the foremost advantages of the invention, especially as regardsthe novel closure members of laminated sheet material, is the widevariety of materials to which they can be eifectively, evenhermetically, sealed. Hermetic sealing is of course dependent uponimperviousness of both the closure member and the container body, aswell as the seal therebetween, but can readily be effected according tothe invention. When either the closure member or the container body isof laminated sheet material, the other member may be selected from avariety of thermoplastic or thermosetting materials such as polystyrene,polyethylene, polypropylene, cellulose acetate, phenolformaldehyderesins, melamine resins, et cetera, as well as glass, wood, paper orpaperboard, metal, ceramics, wax-coated or dipped materials, e.g., waxcoated trays, and the like, and numerous additional materials. The typeof material is only limited in that it must be a material to which theextruded thermoplastic laminant will adhere in congealed or setcondition, and the range of such materials is indeed very broad.Regardless of the materials used, it is preferred to maintain the sealedareas under at least minimal contact pressure during congealment orsetting of the adhesive, as by cooling.

One preferred embodiment of the invention involves the forming, as byvacuum or stamping, of plastic or other sheet materials into continuousor semi-continuous strips, including sheets, of container bodies,filling the formed container bodies with the desired content, providinga continuous or semi-continuous strip, including sheet, of laminatedsheet material of which closure members are to be constructed, saidstrips being with or without predetermined lines or zones of fracture asby means of perforations or cut scores, bringing the laminated sheetmaterial into juxtaposition with the filled but uncovered pre-formedreceptacles or container bodies while in strip form, and sealing thelaminated closure member sheet material thereto, either before or afterbut preferably before severance of the strip into individual containerbodies. When the container closure member is to be sealed against abearing edge and upwardly turned extension thereof in the containerbody, the severance can be effected by means of a heated blade or seriesof blades, which extrude the thermoplastic laminant adhesive outwardlyfrom the cut edges of the cover members during the severance. When aslit or slits are to be provided in the edge areas of the closuremembers, for sealing to a bearing edge of the container body, thelaminated sheet material is provided with such openings in advance ofbringing the sheet material and the performed web of container bodiestogether, the closure member sheet with preformed openings is indexed orbrought into register with the strip of container bodies, and thesealing by extrusion of laminant adhesive from the openings in the edgeareas of the closure member is effected by means of a heated roll orblade or series of blades before or during severance of the strips intoindividual sealed containers.

Inasmuch as the functioning of the sealing and lami nating adhesive ofmy cover or container body construction does not depend on the principleof differential migration by absorption, but rather on extrusion underheat or heat and pressure, the choice of sheet materials which may beused is quite broad, as they may be of equal or differing thicknessesand porosities. In general, I prefer to use a thinner sheet for one ofthe plies of the laminated sheet material which becomes the innersurface of the container or cover. A thicker sheet may form the insidesurface of the container or cover. When the thicker sheet is placed onthe side which will become 1 he outside surface of .the closure memberand/or the container body, it will generally be a pigment coated paperor paperboard to provide a good printing surface and to obtain otheradvantages which will be hereinafter described. At least one ply of thelaminated sheet material must have sufficient strength to providestructural rigidity, and ordinarily both plies will have sufficientstrength for this purpose and will each exceed about ten pounds per inchin tensile strength as determined by TAPPI method T404m. In some cases,the tensile strength of one or both sheets will be much higher whenrequired for specific packaging applications. The thickness of the pliesemployed in the laminated sheet material will generally range from about.002 to about .016 inch, with a thickness of laminant from about .004inch to about .015 inch but usually ranging from about .004 to about.008 inch. While the thickness of the plies as mentioned is usually fromabout .002 to .016 inch, I may employ paperboard sheet material as oneply of the laminated sheet which may have a thickness as great as .03inch.

Any or all base sheet materials employed as stocks for production of thelaminated sheet material may be treated in any of various ways, such asby printing, treating for grease-proofness or wax hold-out, glossing,and the like, and such treatment will ordinarily be applied prior to thelaminating operation. Representative sheet materials include, inaddition to paper and paperboard, parchment papers, papers containingfoil mounted thereon, greaseproof papers, glassine papers, non-wovenfabrics, and the like.

As further indicative of base material stocks suitable for employment inlaminated sheet materials, there may he mentioned the usual paper orpaperboard sheets, including sheets made on a cylinder machine or amultipleheadbox Fourdrinier machine having a number of plies, or heavypaper sheets having only a singly ply. Generally speaking, the basesheet stock may be any fibrous cellulosic or synthetic sheet, but insome cases may include foils or films as one ply thereof. Aluminum foilmay sometimes advantageously be used for one ply, as when the ply is tobecome the inside or outside surface of the container or closure member.In such cases the aluminum foil may be and preferably is mounted on alight paper before gluing or laminating to a second fibrous ply, foilside in or out. For highest possible moisture-vapor proofness, thesesheet stocks may be additionally proofed, including for example drywaxed, semi-waxed, or surface waxed paperboard or paper materials, orpolyethylene-coated materials, or the like. The containers and covers ofthe invention are fabricated of such laminated sheet materials,illustratively paperboard wax-laminated to paper, and will in general befibrous sheets laminated to each other or to foils with suitablelaminating materials as hereinafter more fully described.

In the sheet materials employed for the formation of my heat scalableand especially leakproof containers, the ability of the laminatingadhesive to ext-rude through slits and raw edges provided in certainpreselected areas of the container or closure member construction isessential. When a leakproof or hermetically sealed container isrequired, I have found that it is necessary to extrude laminatingadhesive through such slits and edges in sufficient amount not only toheat seal at contiguous surfaces, but also to cover or bllOCk the rawcut edges of fibrous sheet materials used in the container constructionto prevent migration by wicking of moisture, watervapor, liquids, orgreases through the closure or seams of the container construction.Likewise, even when a leakproof container is not required, as when atacked or tamper-proof container is of interest, a satisfactory bondbetween the closure member and container body, e.g., at a bearing edgeor an extension of said bearing edge, requires that a certain minimumquantity of thermoplastic laminant adhesive be present to provide therequisite boclies of adhesive, by extrusion through one or moreextrusion paths in the container construction, which are necessary for asatisfactory degree of adhesion.

As thermoplastic laminant adhesive for uniting the plies of laminatedsheet materials which are employed in producing the closure members and/or container bodies of the invention, the so-called hot-melt adhesivesare preferred. Moisture-vapor-proof hot melt adhesives based onpetroleum waxes are especially suitable, as these have a high degree ofplasticity and flexibility. Hot melt adhesives based on microcrystallinewaxes are especially preferred. Additional representative laminantadhesives include (A) rnicrocrys-talline waxes of any origin, e.g.,Louisiana, Pennsylvania, or Mid-Continent origin, and/ or paraffin waxesmodified with: (l) synthetic polymers such as butyl rubber,polyisobutylene, polyethylene, copolymers of vinyl acetate and ethylene,(2) aluminum stearate, (3) hydro-philic adsorbents, (4) surfaceactivators, (5) terpene resins, (6) ester gums, (7) rosin derivatives,and the like; (B) low molecular weight polymers such as (l) polystyreneof 4,000 to 20,000 M.W., (2) polyethylene of 2,000 to 12,000 M.W., (3)polyterpenes, (4) isoprene polymers, (5 chlorinated natural andsynthetic rubbers, (6) natural rubbers, and the like; (C) cellulosederivatives such as (1) ethyl cellulose compositions and mixturesthereof with resins, Waxes and plasticizers, (2) nitrocellulosethermoplastics, (3) cellulose acetates or other esters and mixturesthereof with resins and the like; all of which may be suitably modifiedwith various other resins and with plasticizers, according toconventional knowledge and procedure of the art.

The thermoplastic adhesive employed in laminating the sheet materialsshould have the usual flow characteristics of a thermoplastic and may,for example, have a viscosity of at least about 75, and preferably atleast about 150, centipoises in the range of from about ten degrees toabout fifty degrees Fahrenheit above its softening point, e.g., at atemperature of about 220-270 degrees Fahrenheit, as measured byBroookfield Synchroelectric Viscometer or other rotational viscometer ata spindle speed less than ten r.p.m. As previously stated, hot meltcompositions based on hydrocarbon and especially petroleum waxes aresuitable, preferably those based on microcrystalline waxes, and thesemay be increased in viscosity by admixture therewith of viscositybuilders such as polymers of ethylenically unsaturated hydrocarbons,natural gums, gelling agents, or a hydrous adsorbent powder incombination with a surface activator, especially inorganic gellingagents such as hydrated attapul'gite of the like together withnitrogen-containing surface activators, especially fatty-acid amides andalkyl quaternary ammonium salts, or any other viscosity builderindicated previously. The latter type of wax composition, involvingcombinations of microcrystalline or other hydrocarbon waxes withhydrated adsorbents and long-chain paraffinic surface activators, suchas the types mentioned, prepared by expulsion of water of hydration fromthe adsorbent in the presence of the surface activator, are disclosed inmy copending US. patent application Serial No. 133,490 (see Serial No.452,329, a continuation thereof), and are preferred because of theirthixotropic properties, although it is not essential that these beemployed as many others are suitable.

The density of the thermoplastic adhesives employed will ordinarilybefrom about 12 to about 25 or more 13 pounds per ream (3,000 square feet)per each .001 inch of thickness thereof.

I have found that there is a limiting lower level of the amount orthickness of the thermoplastic laminant adhesive to be employed in thelaminated sheet materials for the closure member and/or container body.This is the amount which allows adequate sealing by extrusion withoutundesirable delamination of the laminated sheet material. In general, Ihave found it desirable although not essential to have uninterruptedadhesive exceeding the thickness of the base ply of the laminatedmaterial around and through which the adhesive will be extruded. In anyevent the adhesive will usually be present in an amount of at leastabout fifty-five and preferably at least sixty pounds per ream (3,000square feet). This latter amount is ordinarly suflicie-nt to provide athickness of laminant in excess of .004 inch. With this thickness, thereis sufiicient adhesive material to extrude through the openings providedin the ply or plies of the closure member and/or container body withoutdelamination. This amount of adhesive is also sufficient to extrude outof the cut edges of the closure member and/or container body to seal theformer to the latter or vice versa. Greater thicknesses of laminantadhesive, even exceeding the combined thickness of the base sheetmaterials, may be employed if desired.

I have moreover found the laminated sheet materials of my copending US.patent application, Serial No. 133,521, now US. Patent 3,194,469,ideally suited for use in the construction of heat sealing containersaccording to the present invention.

In the heat sealing of containers of the present invention, it is alsoadvantageous to provide a driving force to assist extrusion of thelaminant adhesive into the desired locations for sealing of thecontainer, especially when a'hermetic seal is desired. Ordinarily, theextrusion may be accomplished by heat or heat and pressure alone,whether sealing with or without external support of the sealing area ofa bearing edge, as by use of frames or mandrels. However, in certaininstances, as in providing a top closure tack or seal for a filledcontainer where the application of excessive pressure would distort thecontainer, I have found it desirable to have a heat-activated drivingforce, such as a volatilizable material, present in the outside ply ofthe laminated sheet material, that is, in the ply opposite to the plycarrying the openings, if any, through which the extrusion of adhesiveis desired. This driving force can ordinarily be simply provided by theaddition of an aqueously or otherwise deposited coating, such as'a clayand/ or pigment bound by any one or more of various adhesives of thestarch, casein, or latex variety. Certain inks may also be employedwhich contain or occlude volatile materials. It is also possible toinclude driving materials in the sheet material employed in thelamination during its production, as in the papermaking step, or toprovide sufficiently high moisture content in the paper to provide thedesirable driving force during heat sealing. During'the heat-sealingstep, such materials apparently assist by creation of sufficient vaporpressure to aid in extrusion and redistribution of the laminant adhesivewithout the application of excessive amounts of external force. AlthoughI do not understand completely all the factors involved, I have foundthe inclusion of mineral clays in the outside ply or in the coating ofthe outside ply, which is the ply opposite to the ply provided withopenings into the intercalated thermoplastic laminant adhesive layer, tobe particularly effective. The provision of such a driving material ismost simply and conyeniently accomplished by including the same on or ina "coatingon the base sheet material which is to be the outer ply of theformed container. Mineral clays and/or pigments in combination with thebase sheet materials are generally preferred in embodiments where theouter plies are of approximately equal thickness.

It is readily apparent that I have provided severaldifferent typecontainers which may be effectively and even hermetically sealed in asimple and facile manner Whether filled with foodstuffs or the like onan assembly line of a processing plant or whether filled and sealed atestablishments which usually do not have available the elaborateapparatus for sealing similar type containers herefore available.

While in the foregoing description and drawings one of the containerbody and the container closure member has been referred to as theclosure member and the other as the container body, it is apparent thatby simple inversion of the components the container closure may in manyinstances become a container body and the container body may become aclosure member. Which ever way the several components are regarded, theapplication of the principles of the present invention are the same, andreversal of the parts in the manner indicated is entirely within thescope and spirit of the invention.

Moreover, it is to be understood that the materials of constructionemployed for what is in the foregoing description and drawingsdesignated a closure member may be employed instead as the materials ofconstruction of the complementary container body and that the materialsof construction shown or disclosed as being the materials ofconstruction of the container body may be employed instead for thecontainer closure member, so that the construction will remain the samebut the materials of construction will be reversed.

According to a preferred embodiment of the invention, the container bodyis provided with a bearing edge for support of the container closuremember. When the term fbearing edge is employed herein, this is to beunderstood as meaning a surface or point of the container body whichprovides support for the container closure member when inserted into orplaced onto the container body and which may in certain embodimentsallow nesting of the closure member within a container body member.

One particularly adavntageous adaptation of the present invention,involving a specific form or type of container, concerns a cancomprising a can wall of laminated sheet material of the typehereinbefore described. The plies of the sheet material mayadvantageously be paper or paperboard for one ply and paper, paperboard,foil or film, or foil or film adhered to paper or paperboard, for asecond ply. Also among the more advantageous materials of construction,especially for an inner ply, may be mentioned grease proofed sheetmaterials, dry waxed sheet materials, and plastic film sheet materials,although as previously indicated the type of sheet material which may beemployed as a ply of the laminated sheet material is widely variable,and the foregoing are mentioned merely as representatively advantageousmaterials of construction. These plies are adhered to each other bythermoplastic laminant adhesive of the type hereinbefore described, andin the usual manner for effecting such laminations, again ashereinbefore described. The lamination of such sheet materials isproductive of a laminated sheet material of the type hereinbefor'edescribed, in which the characteristics of the plies and the laminantand the laminated sheet material are all as hereinbefore described. Uponprovision of the laminated sheet material, substan tiallyparallelogramatic or rectangular carton wall blanks are cut therefrom.At this point, the blanks may be appropriately scored, or they may beappropriately scored prior to or during cutting of the said can wellblanks. When scored, ordinarily two score lines will be provided, so asto allow the folding over of the can blank along first the one and thenthe other score line, to bring an edge area of the one folded portion ofthe blank into juxtaposition with an edge area of the other foldedportion of the blank, so as to provide an area of overlap at which aseam may be effected. The blank may have more than two scores or foldsif desired. Alternatively, in the area of overlap, one or more of thefacing plies of the laminated sheet material of the can wall blank mayalso be provided with one or more openings, e.g., slits or cuts, intothe intercalated thermoplastic laminant adhesive layer thereof, to allowheat sealing of the can wall blank to itself in the area of overlap, orone or more cuts into the intercalated thermoplastic adhesive layer maybe provided in the inner ply of sheet material of the can wall blankadjacent the exposed cut edge of the seam, to allow extrusion ofthermosplastic adhesive laminant out of said cut or cuts and over theexposed edge of said seam by the application of thermoplastic laminantadhesive activating conditions. As a still further alternative, scoringmay be omitted entirely. When such slit or cut into the intercalatedthermoplastic laminant adhesive layer is provided adjacent the exposedraw edge of the seam, this is conveniently done by backcutting,advantageously after providing the unscored or scored can wall blank. Atthis point, a scored and not yet folded can wall blank may be folded andseamed in the area of overlap employing either cold adhesive such asglue, or hot melt compositions, whether or not backcuttin-g adjacent theexposed raw edge of the seam has been effected. When employing anunscored blank, it is advantageously formed into the desiredconfiguration over a mandrel and seamed in the already indicated manner,without however prior folding of the blank upon itself. At this point,in any procedure, the seam may be heated or pressure or both heat andpressure applied thereto to extrude thermoplastic laminant adhesivetherefrom and from any adjacently disposed opening provided by a priorbackcutting operation, if any. A prescored and folded can wall blank maybe erected by means of a mandrel or ring of the retaining type,whereupon any previously scored and folded areas can be heat treated toreestablish continuity of thermoplastic laminant adhesive in such areasand to restore a smooth exterior surface appearance to the previouslyfolded areas. At this point, in any method of operation, the can bottommay be spun on or otherwise secured to the preformed can wall, using anunscored unfolded blank already formed on the mandrel or the scored andpreviously folded blank as just described. Ordinary can lids of metal,e.g., aluminum, tin plate, or the like, or of plastic, paper orpaperboard, or of the same type of laminated material as used inconstruction of the can wall, may constitute the can bottom and/or top.The spinning on of the can bottom is effected in conventional manner,with or without the application of heat to extrude adhesive out of thecut edges of the can wall, thus to provide a thermoplastic adhesivelaminant gasket in the area of sealing engagement between the can walland the can bottom. Alternatively, crimping on of the can bottom usingeither a simple crimp or a double seam crimp or in any other mannerconventional in the art for attaching can walls to can ends may beemployed and, according to the invention, the pressure imparted bycrimping alone is usually adequate to activate the thermoplasticadhesive laminant in the edge areas of the can wall and effect aself-gasketed closure between the can wall and the can end. When the canbottom has been effectively secured to the can wall, the desiredcontents may be introduced, and the can top spun on or otherwise securedin conventional manner, again with or without heat or heat and pressure,and again activation may be adequately effected by the pressure impartedby the crimping operation alone, thereby effecting a self-gasketed sealbetween the can wall and the can top without the application ofadditional activating conditions. The filled, closed, and effectivelygasketed cans may be then packed and stored or shipped or,alternatively, heat may be applied to both ends of the can momentarilyfor purposes of positive fluxing of the thermoplastic laminant adhesiveto provide a more effective seal between the can wall and top and bottomthereof. The heating of both ends is especially significant when ahermetic seal is desired.

Such containers are extremely valuable in that the protective materialof the can wall is not exposed on the inside to the contents, whichamong other things make such containers useful for materials which wouldabrade the inside surface coating of ordinary cans. The wax or otherthermoplastic laminant adhesive material is highly compressive at theseam of the containers, which allows an almost flush joint at such pointin the can wall upon application of minimal pressure thereto. The canshave a high crush resistance and degree of protectiveness, and can bemade water-proof and water-vapor proof and even hermetically sealed ifdesired. When scored and folded, and then erected, according to theinvention, the can wall of the present invention may be caused to loseits memory and reassume an uninterruptedly smooth exterior surface evenin the area of previous folding by the application of heat to thepreviously scored and folded areas, so that there is no or practicallyno springback apparent after this step despite previous scoring,folding, and unfolding during erection of the can wall. This isespecially important when the cans are'of other than circular crosssection. Cans produced in the aforesaid manner have been tested andfound to be not only extremely durable and crushproof, but to providevery high protective properties and to exhibit high water-proof andwater-vapor proof characteristics, and even hermetic characteristics,when produced from otherwise impervious materials of construction forthe can ends. Representative cans made according to the invention andfilled with anhydrous calcium chloride have shown no weight gain due towater-vapor transmission after weeks of exposure at 50% related humidityat 73 F.

As previously stated, ordinary can lids are suitable for can end closuremembers. These are usually provided with flanges to be inserted into thetubular can wall structure for affixing the closure member thereto priorto crimping and/ or sealing, all as well known in the art. A can endclosure member may also be provided with a flange and bead, as shown inFIGURE 16, rather than a flange and crimp. The can wall may also besealed to the end closure member by means comprising slits in one ormore plies thereof, also as shown in FIGURE 16.

While activation of the thermoplastic laminant adhesive has beenillustrated and disclosed by use of heat, heat and pressure, and evenpressure alone in certain circumstances, after the cover member andcontainer body are in sealing engagement, it is to be understood that insome instances the activation may be just before or concurrent withclosing of the container as well as after, as by momentary applicationof high temperature, but in such case application of at least minimalpressure after closing, e.g., after the members are in sealingengagement, is still preferred.

It will be apparent to one skilled in the art that the present inventionmay be embodied in other specific forms without departing from thespirit or essential attributes thereof.

It is therefore desired and intended that the several embodiments hereinspecifically set forth be considered in all respects as illustrative andnot restrictive, reference being made to the appended claims rather thanthe foregoing description and drawings to indicate the scope of theinvention, which is to be understood as limited only by the scope of theappended claims. l i

I claim:

1. The process of producing sealed containers which includes the step ofproviding a plurality of interconnected container bodies each having abearing edge for support of a container closure member and a surface forsealing engagement therewith, filling the formed container bodies withdesired content, providing a laminated sheet material for production ofcontainer closure members, bringing the said laminated sheet materialinto juxtaposition with the filled preformed container bodies, and. thensealing the laminated sheet material thereto by the application ofthermoplastie laminant adhesive activating conditions and severing theconnected container bodies and the laminated sheet material injuxtaposition therewith into individual sealed container bodies, thesteps of sealing and severing being conducted in any order, the saidclosure members at least upon severance having avenues of exit in areasin a ply of said sheet material of their construction which opposesealing surfaces of the container bodies, said laminated sheet materialcontaining sufficient thermoplastic laminant adhesive between its pliesto extrude therefrom through said avenues of exit into contact with saidopposed sealing surfaces of said container bodies when in sealingengagement therewith upon application of said thermoplastic laminantadhesive activating conditions without delamination of said laminatedsheet material or said individual cover members upon severance, saidsealing including the steps of extruding thermoplastic laminant adhesivethrough said avenues of exit into contact with said opposed sealingsurfaces and allowing said adhesive to congeal.

2. The process of claim 1, wherein said avenues of exit comprise the rawcut edges of the severed individual container closure members.

3. The process of producing sealed containers which includes the step ofproviding a plurality of interconnected container bodies each having abearing edge for support of a container closure member, filling theformed container bodies with desired content, providing a laminatedsheet material for production of container closure members, bringing thesaid laminated sheet material into sealing engagement with the filledpreformed container bodies, sealing the laminated sheet material theretoby the application of thermoplastic laminant adhesive activatingconditions, and severing the connected container bodies and attachedlaminated sheet material into individual sealed container bodies, thesaid laminated sheet material of said closure member construction beingprovided with avenues of exit in a predetermined pattern and inpredetermined areas in a ply of said sheet material so as to be inregister with bearing edges of the connected container bodies, saidlaminated sheet material containing sufficient thermoplastic laminantadhesive between its plies to extrude therefrom through said. avenues ofexit into contact with said bearing edges of said container bodies whenin sealing engagement therewith upon application of thermoplasticlaminant adhesive activating conditions without delamination of saidlaminated sheet material or said individual cover members uponseverance, said sealing including the steps of extruding thermoplasticlaminant adhesive through said avenues of exit into contact with saidbearing edges of said container bodies in sealing engagement therewithand allowing the said adhesive to congeal.

4. The process of claim 3, wherein said avenues of exit comprise aseries of recurring openings into the intercalated thermoplasticlaminant adhesive layer of said sheet material, each unit of the seriesinvolving one or more slits which are opposed to the bearing edges of acontainer body when said laminated closure member sheet material isbrought into sealing engagement with said preformed container bodies.

References Cited by the Examiner UNITED STATES PATENTS 2,474,619 6/1949Farrell et al. 229-48 2,896,387 7/1959 Brock 53184 X 3,112,587 12/1963Anderson et a1. 5339 FRANK E. BAILEY, Primary Examiner.

P. H. POHL, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,290,856 December 13, 1966 George G. Rumberger It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

In the heading to the printed specification, lines 4 and 5, for"assignor to KVP Sutherland Paper Company,

Kalamazoo, Mich.," read assignor to Brown Company, column 10, line 65,for "performed" read preformed column 11, line 47, for "singly" readsingle column 12, line 59, for "of" read or column 14, lines 8 and 9,for "here-fore" read heretofore line 65, for "well" read wall column 17,line 11, strike out "said".

Signed and sealed this 26th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. THE PROCESS OF PRODUCING SEALED CONTAINERS WHICH INCLUDES THE STEP OFPROVIDING A PLURALITY OF INTERCONNECTED CONTAINER BODIES EACH HAVING ABEARING EDGE FOR SUPPORT OF A CONTAINER CLOSURE MEMBER AND A SURFACE FORSEALING ENGAGEMENT THEREWITH, FILLING THE FORMED CONTAINER BODIES WITHDESIRED CONTENT, PROVIDING A LAMINATED SHEET MATERIAL FOR PRODUCING OFCONTAINER CLOSURE MEMBERS, BRINGING THE SAID LAMINATED SHEET MATERIALINTO JUXTAPOSITION WITH THE FILLED PREFORMED CONTAINER BODIES, AND THENSEALING THE LAMINATED SHEET MATERIAL THERETO BY THE APPLICATION OFTHERMOPLASTIC LAMINANT ADHESIVE ACTIVATING CONDITIONS AND SEVERING THECONNECTED CONTAINER BODIES AND THE LAMINATED SHEET MATERIAL INJUXTAPOSITON THEREWITH INTO INDIVIDUAL SEALED CONTAINER BODIES, THESTEPS OF SEALING AND SEVERING BEING CONDUCTED IN ANY ORDER, THE SAIDCLOSURE MEMBERS AT LEAST UPON SEVERANCE HAVING AVENUES OF EXIT